A sign informs park goers that Calvert Cliffs are closed due at Calvert Cliffs State Park in Calvert County, Md., on June 10, 2018. (Photo By Kaitlyn Dolan/Chesapeake Bay Program). (Download on Flickr)

Beach goers search for fossils and enjoy the water at Calvert Cliffs State Park in Calvert County, Md., on June 10, 2018. The cliffs have been closed due to unstable rocks and falling debris. (Photo By Kaitlyn Dolan/Chesapeake Bay Program). (Download on Flickr)

Calvert Cliffs, which have been closed due to unstable rocks and falling debris, in Calvert Cliffs State Park in Calvert County, Md., on June 10, 2018. (Photo By Kaitlyn Dolan/Chesapeake Bay Program). (Download on Flickr)

The Jones family, Ben, Phil, Lucy, and Kristen, wades in the Patuxent River after Bernie Fowler's 31st annual Wade-In at Jefferson Patterson Park in Calvert County, Md., on June 10, 2018. (Photo By Kaitlyn Dolan/Chesapeake Bay Program). (Download on Flickr)

Shoes are left on the shore of the Patuxent River during Bernie Fowler's 31st annual Wade-In at Jefferson Patterson Park in Calvert County, Md., on June 10, 2018. (Photo By Kaitlyn Dolan/Chesapeake Bay Program). (Download on Flickr)

Former senator Bernie Fowler claps after the completion and measuring of the &quot;sneaker index&quot; at Bernie Fowler's 31st annual Wade-In at Jefferson Patterson Park in Calvert County, Md., on June 10, 2018. The sneaker index is a non-scientific way of measuring the cleanliness and health of the Patuxent River by wading into the water until Fowler can no longer see his white sneakers. (Photo By Kaitlyn Dolan/Chesapeake Bay Program). (Download on Flickr)

Congressman Steny Hoyer measures for the sneaker index at Bernie Fowler's 31st annual Wade-In at Jefferson Patterson Park in Calvert County, Md., on June 10, 2018. The sneaker index is a non-scientific way of measuring the cleanliness and health of the Patuxent River by wading into the water until Fowler can no longer see his white sneakers. This year's measurement was 36 inches. (Photo By Kaitlyn Dolan/Chesapeake Bay Program). (Download on Flickr)

Congressman Steny Hoyer measures for the sneaker index at Bernie Fowler's 31st annual Wade-In at Jefferson Patterson Park in Calvert County, Md., on June 10, 2018. The sneaker index is a non-scientific way of measuring the cleanliness and health of the Patuxent River by wading into the water until Fowler can no longer see his white sneakers. This year's measurement was 36 inches. (Photo By Kaitlyn Dolan/Chesapeake Bay Program). (Download on Flickr)

Former senator Bernie Fowler smiles as he exits the Patuxent River after Bernie Fowler's 31st annual Wade-In at Jefferson Patterson Park in Calvert County, Md., on June 10, 2018. (Photo By Kaitlyn Dolan/Chesapeake Bay Program). (Download on Flickr)

Bernie Fowler (center) exits the Patuxent River during Bernie Fowler's 31st annual Wade-In at Jefferson Patterson Park in Calvert County, Md., on June 10, 2018. The wade-in began 31 years ago as an event to bring attention to the environmental state of the Patuxent. (Photo By Kaitlyn Dolan/Chesapeake Bay Program). (Download on Flickr)